lv_encoder_emu

lv_encoder_emu ¶

Soft rotary-encoder emulator for LVGL on non-MCU runtimes.

Stand-in for hardware machine.Encoder / rotaryio while developing on desktop (SDL/PG), PyScript, or Jupyter. Each :class:EncoderEmu owns:

a :class:SoftEncoder (position + pushbutton state)
an eventsys :class:~eventsys.EncoderDevice registered on runtime
an LVGL emulator UI (← / Enter / →) on a secondary displaysys surface, in a private focus group (not the app default)

Multiple emulators may coexist in one app (one window/canvas each)::

from board_config import runtime
import display_driver  # primary LVGL first
from lv_encoder_emu import EncoderEmu

emu_a = EncoderEmu(runtime, title="Enc A")
emu_b = EncoderEmu(runtime, title="Enc B")
# emu_a.device / emu_b.device are LVGL encoder indevs on the primary display

Classes¶

SoftEncoder ¶

SoftEncoder(pos=0)

Position / button state for runtime.add_encoder read callbacks.

Same contract apps use with MCU machine.Encoder / rotaryio: a wrapping position integer and a boolean pushbutton.

Methods:¶

read_pos ¶

read_pos()

Zero-arg callable for runtime.add_encoder(read=...).

read_button ¶

read_button()

Zero-arg callable for runtime.add_encoder(button_read=...).

EncoderEmu ¶

EncoderEmu(runtime, *, display=None, attach_devices=None, title='Encoder', width=240, height=80, scale=1, canvas_id=None, button=DEFAULT_ENCODER_BUTTON, target_lv_display=None, soft=None)

One emulated encoder: secondary surface + LVGL UI + eventsys device.

Call after import display_driver so the primary LVGL display exists. The encoder indev is attached to target_lv_display (default: primary).

Parameters:

Name	Description	Default
`runtime`	`board_config.runtime` (or any :class:`eventsys.Runtime`).	required
`display`	Existing secondary displaysys driver, or `None` to create one.	`None`
`attach_devices`	Host devices for `display_driver.attach` (PS/JN); ignored when `display` is created by :func:`make_emu_display`.	`None`
`title, width, height, scale, canvas_id`	Forwarded to :func:`make_emu_display` when creating a display.	required
`button`	Mouse button index for the encoder switch (default `3`, matching `display_driver._encoder_cb`).	`DEFAULT_ENCODER_BUTTON`
`target_lv_display`	LVGL display that receives the encoder indev; default is the primary LVGL display.	`None`
`soft`	Optional existing :class:`SoftEncoder`; created when omitted.	`None`

Attributes¶

soft `property` ¶

soft

:class:SoftEncoder state (position / button).

device `property` ¶

device

Registered eventsys :class:~eventsys.EncoderDevice.

display `property` ¶

display

Secondary displaysys driver for the emulator surface.

bridge `property` ¶

bridge

display_driver.DisplayDriver for the emulator LVGL display.

group `property` ¶

group

LVGL group owning the emulator buttons (not the app default).

root `property` ¶

root

Root LVGL object of the emulator UI.

Functions:¶

make_emu_display ¶

make_emu_display(primary=None, *, width=240, height=80, title='Encoder', scale=1, canvas_id=None)

Create a same-backend secondary display for an encoder emulator.